Oil Shale In-Situ Upgrading by Steam Flowing in Vertical Hydraulic Fractures

Moridis, George J.; Ehlig-Economides, Christine

doi:10.2118/169017-ms

Cited by 9 publications

(9 citation statements)

References 9 publications

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“…Condition (1) implies that the mass advection A has only a small effect on the operator K. It is true if only a small proportion of the reactant exists in the gas phase. Condition (2) implies that K has a small effect on C. Reaction enthalpies are generally neglected in the modelling of ISU [20,21] and we follow this approximation in this work. However, we note that it could have a large impact on the process [22].…”

Section: A New Splitting Method: Sso-ckamentioning

confidence: 99%

“…We note that values for the pre-exponential factors and activation energy are smaller than those reported by [25]. The rock properties are shown in Table 4 and the fluid properties in Table 5, adapted from [10,20,21]. The viscosity of the gas phase is given by: These data are adapted from [20] and the viscosity of the liquid phase is given by [26]: …”

Section: Test Casementioning

confidence: 99%

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Modelling in-situ upgrading of heavy oil using operator splitting method

et al. 2015

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The in-situ upgrading (ISU) of bitumen and oil shale is a very challenging process to model numerically because of the large number of components that need to be modelled using a system of equations that are both highly non-linear and strongly coupled. Operator splitting methods are one way of potentially improving computational performance. Each numerical operator in a process is modelled separately, allowing the best solution method to be used for the given numerical operator. A significant drawback to the approach is that decoupling the governing equations introduces an additional source of numerical error, known as the splitting error. The best splitting method for modelling a given process minimises the splitting error whilst improving computational performance compared to a fully implicit approach. Although operator splitting has been widely used for the modelling of reactive-transport problems, it has not yet been applied to the modelling of ISU. One reason is that it is not clear which operator splitting technique to use. Numerous such techniques are described in the literature and each leads to a different splitting error. While this error has been extensively analysed for linear operators for a wide Julien Maes range of methods, the results cannot be extended to general non-linear systems. It is therefore not clear which of these techniques is most appropriate for the modelling of ISU. In this paper, we investigate the application of various operator splitting techniques to the modelling of the ISU of bitumen and oil shale. The techniques were tested on a simplified model of the physical system in which a solid or heavy liquid component is decomposed by pyrolysis into lighter liquid and gas components. The operator splitting techniques examined include the sequential split operator (SSO), the Strang-Marchuk split operator (SMSO) and the iterative split operator (ISO). They were evaluated on various test cases by considering the evolution of the discretization error as a function of the time-step size compared with the results obtained from a fully implicit simulation. We observed that the error was least for a splitting scheme where the thermal conduction was performed first, followed by the chemical reaction step and finally the heat and mass convection operator (SSO-CKA). This method was then applied to a more realistic model of the ISU of bitumen with multiple components, and we were able to obtain a speed-up of between 3 and 5.

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Section: A New Splitting Method: Sso-ckamentioning

confidence: 99%

Section: Test Casementioning

confidence: 99%

Modelling in-situ upgrading of heavy oil using operator splitting method

et al. 2015

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“…The results of its simulations showed reasonable agreement with data from a field test conducted by Shell (Sandberg et al, 2009). In another work, Lee et al, 2014 investigates the efficiency of oil shale in-situ upgrading by steam flowing. The objective of this work was to find an effective way of heating oil shale reservoirs by steam flowing in horizontal wells and natural vertical fractures.…”

Section: Literature Review Of In-situ Upgrading Numerical Modelsmentioning

confidence: 99%

Hierarchical Coarsening of Simulation Model for In-Situ Upgrading Process

Fucinos

Voskov

Burnham

2017

Day 1 Mon, February 20, 2017

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Faculty of Civil Engineering and Geosciences Department of Geosciences and Engineering Master of ScienceHierarchical coarsening of simulation model for in-situ upgrading process by Raul Fucinos M.Oil shales are sedimentary rocks containing organic matter in the form of kerogen which accounts for more than 5 trillion barrels of oil in place according to Birol, 2010; therefore, oil shales represents a plausible solution for the constantly increasing demand for hydrocarbons. Oil shale production is currently done using two different techniques, surface retorting and in-situ retorting. The last one being the focus of this study. During this process, the sedimentary rock containing the kerogen is brought into a high-temperature environment with oxygen deficit. At this stage, the organic matter is subject to a thermo-chemical decomposition that finally releases the hydrocarbon in liquid and gas forms. This process is also known as pyrolysis. During this process, solid and fluid components experience compositional and physical changes, which requires complex chemical models represented by multiple species and several governing relations.In this work, we first developed a numerical solver for closed systems with simple kinetics models. This initial work allowed us to analyze the dynamic behavior of each component during the chemical decomposition of the kerogen and its impact in the porosity of the system. Then, we described an accurate base model for chemical decomposition of kerogen. This model was then implemented in our inhouse simulator ADGPRS. The model is based on the most recent understanding of pyrolysis process, and it incorporates coupling of chemical kinetics to heat and mass transport. Due to the high number of species, variations of porosity as consequence of the transformation of solid species into fluid products and complex multi-scale structure of porous media, the simulation performance of the high-fidelity model is limited. Therefore, in the second step of this work, we introduce a hierarchy of coarser models to improve the run-time of forward solution without significant reduction in accuracy. We applied coarsening in time, space, and chemical representation, and quantify errors introduced at each coarsening level. In conclusion, we provided recommendations for large-scale modeling of in-situ upgrading process. v

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“…We assign zero capillary pressure for the fracture and wellbore elements. One can find more details of the functions in Lee (2014).…”

Section: Reactionmentioning

confidence: 99%

“…Lee et al (2014) conducted simulation cases of Texas A&M Steamfrac for the oil-shale in-situ upgrading process by using their own simulator on the basis of TAMU FTSim. Steamfrac implements in-situ upgrading of oil shale by using steam flowing in vertical hydraulic fractures and produces converted hydrocarbons.…”

Section: Introductionmentioning

confidence: 99%

A Comprehensive Simulation Model of Kerogen Pyrolysis for the In-situ Upgrading of Oil Shales

2016

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Oil shale, which is composed of abundant organic matter called kerogen, is a vast energy source. Pyrolysis of kerogen in oil shales releases recoverable hydrocarbons. Here, we describe the pyrolysis of kerogen with an in-situ upgrading process, which is applicable to the majority of oil shales. The pyrolysis is represented by six kinetic reactions resulting in 10 components and four phases. Expanding the Texas A&M Flow and Transport Simulator (FTSim), which is a variant of the TOUGH þ simulator (Moridis 2014), we develop a fully functional capability that describes kerogen pyrolysis and accompanying system changes.The simulator describes the coupled process of mass transport and heat flow through porous and fractured media and includes physical and chemical phenomena of reservoir systems. The simulator involves a total of 15 thermophysical states and all transitions between them and computes a simultaneous solution of 11 mass-and energy-balance equations per element. The simulator solves the equations in a fully implicit manner by solving Jacobian matrix equations with the Newton-Raphson iteration method. To conduct a realistic simulation, we account for geological structure of oil-shale reservoirs and physical properties of bulk-oil shale rocks by considering phases and components in the pores. In addition, we involve interaction between fluids and porous media, diverse equations of state (EOSs) for computation of fluid properties, and numerical modeling of fractured media.We intensively reproduce the field-production data of Shell Insitu Conversion Process (ICP) implemented in the Green River formation by conducting sensitivity analyses for the diverse reservoir parameters, such as initial effective porosity of the matrix, oil-shale grade, and the spacing of the natural-fracture network. We analyze the effect of each reservoir parameter on the hydrocarbon productivity and product selectivity. The simulator provides a powerful tool to quantitatively evaluate production behavior and dynamic-system changes during in-situ upgrading of oil shales and subsequent fluid production by thoroughly describing a reservoir model, phases and components, phase behavior, phase properties, and evolution of porosity and permeability.

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Oil Shale In-Situ Upgrading by Steam Flowing in Vertical Hydraulic Fractures

Cited by 9 publications

References 9 publications

Modelling in-situ upgrading of heavy oil using operator splitting method

Modelling in-situ upgrading of heavy oil using operator splitting method

Hierarchical Coarsening of Simulation Model for In-Situ Upgrading Process

A Comprehensive Simulation Model of Kerogen Pyrolysis for the In-situ Upgrading of Oil Shales

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